1. Field of the Invention
The present invention relates to a novel heat-resistant polyester having a specific heat resistance and moldability or processability.
2. Description of the Related Art
Various proposals have been made for the production of polyesters from the starting material 9,9-bis(4-hydroxyphenyl)fluorene. For example, polyesters derived from 9,9-bis(4-hydroxyphenyl)fluorene and terephthalic acid or isophthalic acid are reported in Macromolecule 3,536 (1970), and polyesters derived from 9,9-bis(4-hydroxyphenyl)fluorene and a 3:7 to 7:3 mixture of terephthalic acid and isophthalic acid are reported in JP-A-No. 57-192432).
Furthermore, single polyesters derived from 9,9-bis(4-hydroxyphenyl)fluorene and isophthalic acid or a fatty acid are reported in U.S. Pat. No. 3546165. Although this patent describes the use of terephthalic acid/isophthalic acid (mole ratio=20/80) or terephthalic acid/sebacic acid (mole ratio=60/40), it does not describe the formation of a film.
The present inventors studied these reports, but found that the resultant polymers have disadvantages in that the polymerization degree of each resultant polymer is low, and only a white turbid solution is obtained because, when the polymer is dissolved in a solvent, a portion of the polymer is dissolved therein, and a film having a good appearance and good quality cannot be obtained by casting.
Furthermore, when injection, extrusion, compression, and other molding processes are applied to those polymers, molding is possible only when the processing is carried out at a higher temperature, which causes, for example, decomposition. In particular, the above-mentioned polymer is difficult to use in injection molding.